Orifice piston expansion devices are utilized for metering the flow of pressurized fluid, such as refrigerant medium, along two or more fluid flow paths within a refrigeration or cooling system, such as between the condenser and evaporator coils of a heat pump or other such devices that include a reversible refrigeration cycle. More particularly, existing restrictive members, such as various types of pistons are used, within flow control distributor housings, to perform the required metering and bypass functions, which are well known in the art. Such existing expansion devices and pistons are shown and described, in U.S. Pat. No. 4,896,696, to Bradley et al. and in even more detail in U.S. Pat. No. 5,894,741 to Durham et al., which is also assigned to the assignee of the present invention. Such prior art flow control distributor housings were designed to generally receive only one style of such restrictive members or pistons.
In addition to the above-noted references, the patent literature includes a large number of orifice expansion devices or the like and included in this art are: U.S. Pat. No. 5,265,438 to Knowles et al.; U.S. Pat. No. 5,893,273 to Casiraghi; U.S. Pat. No. 6,363,965 B1 to Carmack et al.; U.S. Pat. No. 6,367,283 B1 to Ederle; and U.S. Pat. No. 6,560,987 B2 to Kreger et al. While the noted Kreger et al. patent discloses a cartridge for a restrictor, this cartridge only provides a seat for a bullet nose type of restrictor and will not accommodate the remaining piston styles. In addition, and importantly so, the cartridge is subsequently brazed in place and, consequently, not replaceable. It is deemed that none of the prior art structures, set forth in the noted references, pertain to the orifice expansion device, the improved orifice expansion device and the restrictor insert, of the present invention.